.a{
    position: absolute;
    width: 500px;
    height: 450px;
    left: 50%;
    border: 1px solid black;
    top:50%;
    transform: translate(-50%,-75%);
    box-shadow: 5px 10px 20px #666;
    border-radius: 10px;
}
.a h3{
    text-align: center;
    
    margin-top: 10px;
    margin-bottom: 15px;
    
    
}
.b{
    margin: 20px;
}
